Self-contained fire detecting and warning apparatus



D. A. WHITE Aug. 4,-1970 SELF-CONTAINED FIRE DETECTING AND WARNING APPARATUS Filed March 27, 1967 2 Sheets-Sh eet 1 Aug. 4, 1970 D. A. WHITE 3,522,595

SELF-CONTAINED FIRE DETECTING AND WARNING APPARATUS Filed March 27, 1967 2 Sheets-Sheet 2 INVENTOR.

United States Patent ABSTRACT OF THE DISCLOSURE A warning apparatus responsive to the presence of an excessive temperature condition occurring in the interior of a building or within the structure thereof and adapted to be permanently mounted over a conventional electric outlet box of the type used to house a wall switch or receptacle. The apparatus also functions as=the cover plate of the outlet box and its circuitry is adapted to be energized by the electrical wiring conventionally found therein. Furthermore, the present invention operates independently of, and does not interfere with the normal use or operation of a wall switch or receptacle housed in the outlet box. t

BACKGROUND OF THE INVENTION The present invention relates to a fire detection and Warning device especially adapted for use in homes and other buildings and which provides an audible or visual warning, as may be desired, indicating the.presence of an excessive temperature condition occurring within the interior of a building or within the structure thereof.

In recent years there has been an increasing demand for a low cost reliable household fire alarm that would be capable of sensing a fire in a home or structure and alarming its occupants, thereby allowing them sufficient time to escape before the fire has appreciably spread. While there have been and are presently many devices capable of performing the aforestated function, they have met with consumer objection for one or more of the following reasons. The primary objection to most fire alarm devices and systems has been their excessive initial cost which is brought about by the fact that they require a complex initial cost by providing compact batter yor spring-powheat sensing devices, extensive wiring, and a'siren or the like. While there have been attempts to reduce this high initial cost by providing compact battery or spring-powered self-contained units, they have generally failed to instill the confidence and offer the reliability that is essential for the consumer to have for a device of this type, since a battery could grow weak or fail and a spring .could run down or sufier mechanical failure before the alarm was sensed by, for example, a person who was sleeping. There are also a'number of fire alarm devices that plug into existing wall receptacles, but they always present the possibility of their being dislodged during cleaning, or by a child or pet. Additionally, these aforemented self-contained units are only responsive to the air temperature of the room in which they are located so that any heat build-up within the walls of the building, such as would be caused by an electrical fire within the walls or a fire on the outside of the building, would not be detected until after considerable damage and escalation of the fire had occurred.

SUMMARY OF THE INVENTION Accordingly, it is the general aim of the present invention to provide a new and improved, compact and economical fire sensing and warning device that is simply and permanently installed, yet provides a degree of reliability and sensitivity that has heretofore been possible with conice siderably more complex and costly equipment and installation.

A related object of the invention is to provide an improved fire sensing and warning device that detects the presence of an excessive temperature both in the interior space and within the structure of a building.

It is another object of the invention to provide a low cost and reliable fire sensing and alarm device that can be easily installed in a prexisting electrical outlet box in a building, utilizing the wiring existing therein, and without interfering with the use and operation of a switch or receptacle that would be housed in the outlet box.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the invention will appear from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front perspective view of an exemplary fire sensing and alarm apparatus embodying the features of the present invention;

FIG. 2 is an exploded rear perspective view of the fire sensing and alarm device shown in FIG. 1, here depicting an exemplary installation in conjunction with an outlet box housing a wall switch;

FIG. 3 is an exploded front perspective view of an exemplary installation of a device similar to that shown in FIG. 1 and 2, but for use with an outlet box housing a receptacle;

FIG. 4 is a diagram of an exemplary circuit that finds use in the present invention;

FIG. 5 is a perspective view illustrating a modified fire sensing and alarm device embodying the features of the present invention; and

FIG. 6 is a perspective view illustrating a remote fire sensing component which finds use in the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to 'FIGS. 1, 2, and 4, an exemplary fire sensing and warning device, generally indicated at 10, is illustrated, the device including a cover member 11 adapted to overlie a conventional wall outlet box 35 (FIG. 2) and having an integral component housing 12 which is provided with a heat actuated alarm circuit generally indicated at 22 and depicted schematically at FIG. 4.

As here shown, the cover member 11 is provided with a rectangular aperture 13 and a pair of holes 14 and 15- so that it can receive and be permanently secured, by screws 17 and 18, to a conventional wall switch 16 (FIG. 2) mounted in the outlet box 35 in the same manner as is a conventional type of switch plate.

Referring specifically to FIGS. 2 and 4, the heat actuated alarm circuit 22 is seen to comprise a heat responsive switch 23 connected in series to an audible warning component 24 and a pair of lead wires 30 and 32 which connect the circuit to a current source. In addition, the pilot light 25 is wired in parallel with the exemplary circuit 22 so as to indicate that the circuit 22 has been properly connected to a current source. In addition the continuous operation of the pilot light 25, after the installation of the device 10, indicates that current is available to the circuit 22. The heat responsive switch 23 can be of any one of several types that are responsive to either a fixed or variable preselected temperature range.

While not utilized in the illustrated embodiment of the present invention, a second temperature responsive switch could be wired in parallel with or used in the place of the switch 23 in order to actuate the warning component '24 in response to an excessive temperature drop occurring within the building due to, for example, a heating system failure. In addition, it is contemplated that the circuit 22 could utilize a smoke sensing switching device as replacement for, or in addition to, switch 23 without departing from the spirit and scope of the present invention.

In accordance with one of the important aspects of the present invention, provision is made to install the exemplary fire sensing and warning component in conjunction with an existing wall outlet box in a simple and reliable manner without interfering with its previously intended function. This is accomplished by first providing the circuit 22 with a continuous current source. To this end, lead wire 30 (FIG. 2) is connected to the current carrying line 28 at the terminal 29 of the wall switch 16 mounted in the outlet box 35, which for purposes of illustration is electrically grounded. In order to complete the connection of the circuit 22, the other lead wire 32 is grounded to the outlet box 35 through the frame of the wall switch 16 by means of the screw 31 which is used to install the switch 16 in the outlet box. The cover member 11 is then afiixed to the wall switch 16 by screws 17 and 18 in the same manner as would be used in installing a conventional wall switch plate. It will be readily apparent to one skilled in the instant art, that instead of being grounded to the outlet box 35, the lead wire 32 could alternatively be connected to the other current carrying line 27. This would be done, for example, in the case of a non-grounded outlet box or where the illustrated wiring might be prohibited by local electric code.

In carrying out the present invention, provision is made for actuating the warning device 24 in response to an excessive temperature condition occuring within the interior of the building wherein it is installed. To accomplish this, a plurality of slots 40 (FIG. 1) are provided in the component housing 12 so that the heated air resulting from the excessive temperature condition can contact the heat responsive switch 23. The component housing 12 is also provided with a 'grill 41 to direct the audible signal emitted 'by the audible warning component 24 into the interior of the building, and a hole 42, through which the pilot light 25 can be readily viewed for the previously mentioned purposes.

It is an additional aspect of the present invention to provide a device as heretofore described which will also be responsive to an extreme temperature condition occurring within the structure of a building. To accomplish this, a slot 44 (FIG. 2) is provided at the rear of the component housing 12 which, upon installation of the cover member 11, establishes direct air communication between the outlet box 35 and the interior of the component housing 12 wherein the heat responsive switch 23 is located. Thus, in a situation where an excessive temperature condition occurs within the wall in which the outlet box 35 is mounted, the air in the outlet box will be heated and pass through the slot 44 which in turn will close switch 23 and thereby actuate the audible warning component 24. It will be appreciated by one skilled in the instant art that this will occur long before the interior air of the building would have been raised to an excessive temperature sufiicient to activate the circuit 22 through the slots 40 which, as previously described, open directly to the interior of the building.

If it were desired to have additional locations in the interior of the building where the presence of an excessive temperature condition would activate the audible-warning component 24 before the air heated thereby reaches the switch 23, one or more remote heat responsive switches 43 as depicted in FIG. 6 could be provided without departing from the scope and spirit of the present invention. The remote switch 43 would operate in parallel with the switch 23 and the connection therebetween could be accomplished by a twin lead wire or by any number of other known methods such as radio waves. It will be readily apparent that in an analogous manner, additional remotely positioned warning components (not shown) could also be provided.

In addition, while the present invention is adapted to be able to utilize the preexisting electrical wiring in a building as a power source, it is contemplated that the emergency batteries (not shown) that would become automatically connected across lead wires 30 and 31 in the event of a power failure, could also be provided as an additional measure of reliability and safety without departing from the scope and spirit of the present invention.

Turning next to FIGS. 3 and 5, there are shown several modified types of the fire sensing and warning device 10, somewhat similar in construction and operation thereto. In view of the similarity betweenthese modified types and the exemplary device 10 already described, like parts in these modified types will be designated by identical reference numerals and those parts not common will be designated by different reference numerals.

In FIG. 3, an embodiment-0f the present invention is illustrated and generally indicated at 10a, which is essentially identical to the exemplary device 10 previously described, but here adapted to be installed at an outlet box 35, provided with a conventional electrical receptacle fixture 47. To accomplish this, the cover member 1101 is provided with a pair of apertures 48 and 49, and a hole 50 so that it can receive the exposed portion of the receptacle 47 and be permanently secured by screw 52 thereto, in the same manner as would be a conventional receptacle plate. To provide current for circuit 22, it is contemplated that lead wires 30 and 32 will be attached to the terminals 54 and 55, respectively, of the receptacle 47, which are connected to the current carrying lines 27 and 28.

The modified device 10b, shown in FIG. 5, is similar to that of 10a, but it will be seen that lead wires 30 and 32 are provided in the form of a plug member adapted to be inserted in receptacle 47 so as to simplify and facilitate installation. It will be appreciated that the cover member 11b can still be permanently installed in a manner similar to that of a conventional receptacle plate by screw 57. Additionally, circuit 22 is provided with a single receptacle member 58 so that there will be no reduction in the number of available receptacles when this embodiment is employed.

While the exemplary embodiments heretofore described have been depicted for use in conjunction with a conventional type ofoutlet box, it is understood that the scope and spirit of the present invention also predicates its use in conjunction with other types of outlet boxes that would provide a current source, such as, for example, those intended for ceiling fixtures, intercommunication equipment, telephones, and the like.

In conclusion it is pointed out, that in its marketable embodiments, the present invention could be integrally provided with an electrical switch or electrical receptacle prewired to the circuit 22 in order to simplify installation and to provide a device more readily adapted to serve the replacement market.

I claim as my invention:

1. A temperature responsive warning device for use in conjunction with a building structure having at least one electrically wired outlet box opening into the interior thereof and being of the type used to house a conventional electrical fixture such as a wall switch, plug receptacle, or the like, said device comprising:

(a) A plate adapted to be permanently secured in a position generally overlying the outlet lbox opening and adapted to receive a preexisting conventional electrical fixture installed in the outlet box in a manner permitting functional operation of the fixture;

(b)An encloesd housing afiixed to said plate and provided with an opening establishing air communication between the interior of said housing and the interior of the building structure;

(0) Electrical circuit means provided in said housing,

said circuit means being capable of sensing the occurrence of an excessive temperature condition of a preselected magnitude within said housing and issuing a perceptible warning in response thereto; and

(d) Said circuit means adapted to be connected to and energized by the electrical wiring in the outlet box.

2. The device as set forth in claim 1 wherein the conventional electrical fixture comprises a switch.

3. The device as set forth in claim 1 wherein the conventional electrical fixture comprises a plug receptacle.

4. The device as set forth in claim 1 wherein said housing is provided with a second opening establishing air communication between the interior of said housing and the interior of the outlet box.

5. The device as set forth in claim 4 wherein the conventional electrical fixture is a switch.

6. The device as set forth in claim 4 wherein the conventional electrical fixture is a plug receptacle.

7. The device as set forth in claim 1 wherein said plate is adapted to be mechanically inserted into a conventional plug receptacle and mechanically attached thereto whereby said insertion will establish said connection and energization of said electrical circuit means and the function of said conventional plug receptacle will be retained.

8. The device as set forth in claim 7 wherein said fixture comprises a wall switch.

9. The device as set forth in claim 7 wherein said fixture comprises a plug receptacle.

10. The device as set forth in claim 3 further including a plug member carried by said plate and adapted to engage said conventional plug receptacle, thereby connecting said circuit means to the electrical wiring in the outlet box when said plate is permanently secured in the aforesaid position overlying the outlet box opening.

11. The device as set forth in claim 1 wherein said circuit means includes a temperature responsive switch and an audible warning device, said switch adapted to energize said warning device upon its exposure to a preselected air temperature in said housing, and said warning device adapted to direct its audible output into the interior of the building structure.

References Cited UNITED STATES PATENTS 3,320,601 5/ 1967 Yankus 340227.1 2,804,609 8/ 1957 Sussman 340227.1 3,274,578 9/1966 Bleck et al 340-416 3,334,340 8/1967 McConnell 3403 10 X DONALD J. YUSKO, Primary Examiner P. PALAN, Assistant Examiner US. Cl. X.R. 

